Gene chips are very useful in the study of gene function and recently there are many people devoting to improve the quality of the gene chips, such as sensitivity, sequence recognition capability, detection speed and operation range, etc., and one of the key achievements is the sensing probe.
Silicon Nanowire-Field Effect Transistor (SiNW-FET) has been proven as a sensor for chemical molecules or biological systems, which has the characteristics of high specificity, label-free detection, low requirement of sample amount, and fast screening. Also, its sensitivity is better than the optical detection platform. Thus, the Silicon Nanowire-Field Effect Transistor (SiNW-FET) biosensor is a platform with development potential. Nanowire FET biosensors are electrical detection platforms, which depends on external electrical fields to affect the electrical conductivity of the nanowires to determine the reaction/behavior of the biological molecules on the nanowire surface through the change of the electrical conductivity. In addition, most carriers are almost always charged, such as proteins and DNA, so when the surface carrier is disposed on the surface of the nanowire, the carrier would directly affect the conductivity of the nanowire and decrease the detection capability of the nanowire for subsequent samples. Also, nanowire FET biosensors are very sensitive to the salt concentration of the detection surface (so called debye length), and when the salt concentration of the detection surface is high, the detection length on the FET surface becomes short and the field effect becomes limited and insensitive to the surface detection.